(19) |
 |
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(11) |
EP 1 215 910 A3 |
(12) |
EUROPEAN PATENT APPLICATION |
(88) |
Date of publication A3: |
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10.09.2003 Bulletin 2003/37 |
(43) |
Date of publication A2: |
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19.06.2002 Bulletin 2002/25 |
(22) |
Date of filing: 03.12.2001 |
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(84) |
Designated Contracting States: |
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AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR |
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Designated Extension States: |
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AL LT LV MK RO SI |
(30) |
Priority: |
07.12.2000 GB 0029850 31.08.2001 GB 0121197
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(71) |
Applicant: SONY UNITED KINGDOM LIMITED |
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Weybridge KT13 0XW (GB) |
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(72) |
Inventors: |
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- Pelly, Jason Charles
Reading, Berkshire RG6 4DU (GB)
- Keating, Stephen Mark
Reading, Berkshire RG6 3AB (GB)
|
(74) |
Representative: Pratt, Richard Wilson et al |
|
D. Young & Co, 21 New Fetter Lane London EC4A 1DA London EC4A 1DA (GB) |
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(57) Material is represented by transform coefficients represented by digital numbers.
A method of perceptibly watermarking the material comprises the steps of: changing
representations of the said numbers according to an invertible algorithm without changing
the number of bits in the said numbers; and encoding the changed n bit numbers to
effect compression encoding of the material.